My U.S. Pat. No. 3,802,731 describes a grapple assembly for a backhoe unit which was useful, for example, for demolition of buildings, clearing of building sites, and raking of the ground to remove small articles of debris. The grapple unit included a stationary lower jaw which was mounted to the forwardly extending stick of a backhoe unit, and also an upper jaw which was closeable upon the lower jaw to crush debris therebetween.
Although the above-described grapple assembly has proved valuable for its intended purposes, it has several limitations which have proved undesirable. The lower or back jaw of the grapple assembly was capable of scraping or raking the ground only in a forward, or outward, direction from the swinghouse of the backhoe; similarly, only a frontal attack could be made by the jaws of the grapple upon a building to be demolished. Further, long objects such as pipes or lengthy timbers, which tend to become aligned transversely in the jaws, could be properly placed in a suitable elongated truck bed or the like only by moving the backhoe itself so as to align the pipe or timbers longitudinally with the truck bed. Also, the orientation of the back jaw to the ground could be adjusted only through adjustments of the boom or stick connecting the back jaw to the swinghouse of the backhoe. Such adjustments for the purpose of properly orienting the back jaw limit the remaining freedom of the stick and boom to move the jaws as desired.
A grapple assembly for a backhoe unit which would avoid the problems discussed above, and which would permit the jaws of the grapple assembly to be properly oriented without requiring gross motions of the stick or boom, is greatly to be desired.